//////////////////////////////////////////////////////////////////////////////////
//   Copyright 2011   Mark Price     mark at epickrram.com                      //
//                                                                              //
//   Licensed under the Apache License, Version 2.0 (the "License");            //
//   you may not use this file except in compliance with the License.           //
//   You may obtain a copy of the License at                                    //
//                                                                              //
//       http://www.apache.org/licenses/LICENSE-2.0                             //
//                                                                              //
//   Unless required by applicable law or agreed to in writing, software        //
//   distributed under the License is distributed on an "AS IS" BASIS,          //
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   //
//   See the License for the specific language governing permissions and        //
//   limitations under the License.                                             //
//////////////////////////////////////////////////////////////////////////////////


package com.epickrram.store.onheap;

import com.epickrram.store.ByteReaderHandler;
import com.epickrram.store.ByteWriterHandler;
import com.epickrram.store.SequenceTable;
import com.epickrram.store.Store;

public final class ByteBufferStore implements Store
{
    private final CopyByteWriter byteWriter = new CopyByteWriter();
    private final ByteBufferOffsetByteReader byteReader;
    private final byte[] buffer;
    private final SequenceTable sequenceTable;
    private final long size;
    private int offset;

    public ByteBufferStore(final long size, final long minMessageSize)
    {
        buffer = new byte[(int) size];
        this.size = size;
        byteReader = new ByteBufferOffsetByteReader(buffer);
        sequenceTable = new ArraySequenceTable();
    }

    @Override
    public synchronized void put(final long sequence, final ByteWriterHandler byteWriterHandler)
    {
        byteWriter.begin();
        byteWriterHandler.write(byteWriter);
        byteWriter.commit();

        int recordOffset = offset;
        final long recordLength = byteWriter.getLength();
        if(recordOffset + recordLength > size)
        {
            recordOffset = 0;
        }
        offset += recordLength;

        System.arraycopy(byteWriter.getBuffer(), 0, buffer, recordOffset,
                (int) recordLength);
        sequenceTable.put(sequence, recordOffset);
    }

    @Override
    public synchronized void get(final long sequence, final ByteReaderHandler byteReaderHandler)
    {
        final long recordOffset = sequenceTable.get(sequence);
        byteReader.setOffset(recordOffset);
        byteReaderHandler.read(byteReader);
    }
}